solaise Posted February 23, 2021 Report Share Posted February 23, 2021 Hello I am in the process of rebuilding the carbs (AUC6040) on my 1963 TR4. I am new to this universe so please bear with me if the terminology is imprecise! The rebuild was going well with new jets and fittings, new needle added and centred, free travel on the pot, float chamber cleaned and valve replaced and float hinge clearance adjusted... until I turned to the throttle spindle. The screws holding in the throttle disc showed some signs of being abused in the past, and one of them sheared in half leaving the stub still in the spindle. The only way I could get the disc out was to drill the rest of the screw out. This damaged the threads in the spindle but I now have the old disc removed and spindle out. I have a new spindle (and disc) as part of the rebuild kit, but the throttle stop seems to be well fixed to the old spindle. There seems to be a pin holding in place, but I not sure if or how this will come out. The supplier of the refurb kit, Burlen suggested this can indeed be removed but I am not sure how to approach this. They also suggested to cut the new spindle down to size and drill a new hole for a pin to hold the throttle stop. Has anyone any general advice on doing this? How do I know which end of the pin to push on the old (if indeed that is how it is to come out)? As for drilling a new hole, any tips apart from buying a bench drill and small bit? (even if I buy a new throttle stop, presumably the spindle still needs a hole drilling) Anything to be aware of before hacking some length off each side of the spindle to match the original? For my general info, how do I tell if the throttle disc needs replacing anyway? (now wishing I had left it alone!) There is lots of talk about bushes holding the spindle in place (teflon or other), mine had none, and has no play either, I am assuming this means I can simply reinsert the new spindle? Thats probably enough questions for a first post. Thanks in advance. Quote Link to post Share on other sites
Lebro Posted February 23, 2021 Report Share Posted February 23, 2021 30 minutes ago, solaise said: Hello I am in the process of rebuilding the carbs (AUC6040) on my 1963 TR4. I am new to this universe so please bear with me if the terminology is imprecise! The rebuild was going well with new jets and fittings, new needle added and centred, free travel on the pot, float chamber cleaned and valve replaced and float hinge clearance adjusted... until I turned to the throttle spindle. The screws holding in the throttle disc showed some signs of being abused in the past, and one of them sheared in half leaving the stub still in the spindle. The only way I could get the disc out was to drill the rest of the screw out. This damaged the threads in the spindle but I now have the old disc removed and spindle out. I have a new spindle (and disc) as part of the rebuild kit, but the throttle stop seems to be well fixed to the old spindle. There seems to be a pin holding in place, but I not sure if or how this will come out. The supplier of the refurb kit, Burlen suggested this can indeed be removed but I am not sure how to approach this. They also suggested to cut the new spindle down to size and drill a new hole for a pin to hold the throttle stop. Has anyone any general advice on doing this? How do I know which end of the pin to push on the old (if indeed that is how it is to come out)? As for drilling a new hole, any tips apart from buying a bench drill and small bit? (even if I buy a new throttle stop, presumably the spindle still needs a hole drilling) Anything to be aware of before hacking some length off each side of the spindle to match the original? For my general info, how do I tell if the throttle disc needs replacing anyway? (now wishing I had left it alone!) There is lots of talk about bushes holding the spindle in place (teflon or other), mine had none, and has no play either, I am assuming this means I can simply reinsert the new spindle? Thats probably enough questions for a first post. Thanks in advance. Hi. Firstly I'm a bit surprised that the new spindle did not come ready drilled. As for which end to knock the pin out from, choose the end with the least "swelling" as that will pass through the shaft more easily. It is important that the hole in the new shaft is at the same angle relative to the disc holes as the old shaft, so some careful measurements required there. A bench or pillar drill would be pretty essential to get the hole central, & at 90° to the shaft. No problem with shortening the shaft,(err on the long side) put a chamfer on each end to ease fitting into the carb. Normally it is the spindle that wears, not the carb body. & if you can feel no play, then perhaps you should have left it alone ! Where about's are you ? If you wish I could prepare the shaft for you, I have the right sort of equipment to do so. anyway, good luck. Bob. Quote Link to post Share on other sites
John L Posted February 23, 2021 Report Share Posted February 23, 2021 Its worth watching this guy he has a lot of useful info that may help you, https://www.bing.com/videos/search?q=su+throttle+shaft+bushing&docid=608045177993889851&mid=E6993EEB4830F1D2FBD0E6993EEB4830F1D2FBD0&view=detail&FORM=VIRE John Quote Link to post Share on other sites
Richardtr3a Posted February 23, 2021 Report Share Posted February 23, 2021 (edited) The pin is tapered and needs to be removed with a punch. The new hole has to be 3mm and I have just bought some 3mm drills on ebay. However I am not confident in being able to drill accurately by hand . It has been suggested that it needs to be trial fitted with some loctite and next day drill the hole .This may work. When I find an answer I will let you know. Are you based in the UK ? Good luck Richard & B Edited February 23, 2021 by Richardtr3a Quote Link to post Share on other sites
solaise Posted February 23, 2021 Author Report Share Posted February 23, 2021 Thanks for the replies! 1 hour ago, Lebro said: then perhaps you should have left it alone ! Yes, very much what I am feeling at the moment. I held the carb body with the disc closed up to a light a could see gaps around (small but visible) so decided to replace it as I had the parts and the carb in pieces anyway. Regretting that now. 1 hour ago, Lebro said: I could prepare the shaft for you, I am going to see if I can borrow a bench drill and have a go at the hole (and if that backfires then ask nicely) For future ref, how close fitting should a disc be in the carb body, and do these discs themselves get worn or is it mostly the spindle that wears? They were pretty black and covered in soot, what should I be looking for here? Tom Quote Link to post Share on other sites
RogerH Posted February 23, 2021 Report Share Posted February 23, 2021 Hi Tom, the disc are a reasonable fit ion the body but they must a degree of clearance for tick over. Note on your new discs that the circumference has a beveled edge. Make sure these line up with the body. Roger Quote Link to post Share on other sites
Drewmotty Posted February 23, 2021 Report Share Posted February 23, 2021 The tapered pin holding the stop has three grooves punched in the sides which are deeper at the bigger end of the taper pin. They can usually be seen on one end of the fitted pin which should be punched out with a suitable drift from the opposite end. A bit f heat from a paint stripping gun always helps. Fit the new shaft and butterfly temporarily, with the butterfly held tightly closed centralise the shaft by equalising the axial play and tighten the screws to hold it in place. I then fit the stop with locktite retainer ( I guess that superglue will work) so that the stop screw tang is parallel with its stop and with the correct clearance feeler between the carb body and lever, I think it’s 0.015”. This clearance can then be adjusted on final assembly by by sliding the butterfly sideways in the shaft before tightening the screws , which is why we’ve previously equalised the play. the position can then be checked prior to drilling and if needs be disassembled for another try. Once all is confirmed correct the spindle can be removed for drilling with the lever bonded in place. I use a drill the size of the existing hole to spot a centre on the shaft from both sides and then drill undersize half way through from each side and then full size from one side once the holes are through. Start with a drill the same size as the small end of the pin. Quote Link to post Share on other sites
Steve Priest Posted March 1, 2021 Report Share Posted March 1, 2021 Hi, This is also a job I have lined up to do. I queried the lack of throttle stop hole with Burlen and this is what they said: "The spindles are not drilled as the best position for the throttle stop will vary and is best fixed once the carburetter is built up. Our restorers stick the throttle stop in place with Loctite before they drill the hole for the pin." This drawing on their website gives the throttle stop clearance and end float: https://sucarb.co.uk/technical-h-type-carburetter-replacement-spindle-and-brushes Good luck! Steve Quote Link to post Share on other sites
Charlie D Posted March 1, 2021 Report Share Posted March 1, 2021 On 2/23/2021 at 3:59 PM, solaise said: "The screws holding in the throttle disc showed some signs of being abused in the past" Tom, Not sure if you know this but the screws have a slot in them that you open up once all is screwed together. Maybe that is why you thought they were "abused". Remember to open them up to lock the screws in position before you put the carbs back on the engine. (Possibly this is why one sheared when you tried to take it out. You need to close up the slot first before you try to unscrew them..) Charlie Quote Link to post Share on other sites
solaise Posted March 19, 2021 Author Report Share Posted March 19, 2021 Thanks to all for the replies and input. I now have the spindle drilled and throttle stop screwed back in and finished the rebuild. I ended up using a bench drill and 3mm bit after marking the hole by comparing it to the old one. (Next time I would use the tip above and glue it in place and then mark and drill.) To my great surprise and pleasure, the car starts and runs pretty smoothly just from the initial tuning. First item on v long listed - tick. Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.